function f = func(x)
    fun1 = x(1) + 10 * x(2);
    fun2 = sqrt(5) * (x(3)-x(4));
    fun3 = (x(2) - 2 * x(3))^2;
    fun4 = sqrt(10)*(x(1) - x(4))^2;
    f = (fun1)^2 + (fun2)^2 + (fun3)^2 + (fun4)^2;
end

